The manner in which respective teeth of a rotating gears mesh is a subject that has been studied for many years for there exists an optimum quality of meshed engagement between their respective teeth that enables maximum power transfer between the gears with minimum noise and wear to the teeth. The quality of meshed engagement between rotating gear teeth includes such factors as the shape and surface finish of the respective teeth, concentricity, and the pitch diameter line of contact therebetween as is well known to those skilled in the art.
The fact that a particular gear pair has been matched to provide a desired quality of meshed engagement therebetween does not mean that such is readily reproduceable in a manufacturing environment due to factors including variations in metal quality, variations in lubrication, and tool wear that are apt to occur during the process of making a quantity of the particular gear pair.
In order to ascertain and maintain a desired quality of meshed engagement between a quantity of manufactured gear pairs, many tests have been devised over the years to compare the mesh engagement quality of a particular chosen gear pair set with some pre-established quality standard. The tests, however, have characteristically been mechanical in nature involving various means for measuring displacement of at least one of the gears, analyzing noise levels while rotating, or perhaps examining shadow grams of the gear pair in a stationary condition. Although such tests have been helpful, they often require costly equipment and may lack the level of accuracy and repetitivity desired.
A need, therefor exists, to provide a simple, low cost, highly repetitive and accurate method of determining gear mesh quality between selected gear pairs which eliminates the highly mechanical nature of such methods heretofor used. It has been discovered quite by accident that such need is highly satisifed when the mechanical elements heretofor employed for such measurement are eliminated and replaced by stroboscopic and optical refractance principles.